Apparatus for centerless grinding or polishing



Dec. 27, 1932. I R. w. FULLER y 1,892,453

'APPARATUS FOR CENTELESS GRINDING OR PQLISHING Filel Jan. 20. 1927 4Sheets-Sheet 1 0 i0 2323i f l' j# r.- alf/AU..

Dec. 27, 1932.

` R. w. FULLER APFARATUS Fon cENTERLEs's GR-INDING on PoLIsnING FiledJan; 2.o. 1927 -4 sheets-sheet 2 K mx.. SQ Nm Q R. W. FULLER Dec. 27,1932.

'APPARATUS FOR CENTERLESS GRINDING OR POLISHING- I Filed Jan. 20, 1927`4 SheetS-Sheet 3 De@ 27, 1932 f R. w. FULLER Y 1,892,453 APBARATUS Fon`cENTERlkass GRIND ING oh POLISHING 'Filed Jan. go. 192'/ .l 4sheets-sheet 4 A erably ilTthe torm of a mov'ng belt, the work PatentedDec. 27, 19,32

PATENT OFFICE Q RUF'S W. vFULLER, vO11" DEERFIELD, MASSACHUSETTS,ASSIG'NOR T0 PRODUCTION MACHINE COMPANY, GREENFIELD, MASSACHUSETTS, ACORPORATION 0F MASSA- cHUsETTs APPARATUS ron oEN'rERLEss saumure onPoLIsHING Application lcd January 20, 192i. Serial No. 162,300.

'Ihe present invention relates to methods and apparatus for centerlessgrinding or .polishing and more particularly to methods and machinesadapted for grinding or polishling taper Work.

The object ot thc present invention is to provide a method and machineby which either taper or straight work may be ground or polished withoutthe `necessity of chucking the work or mounting it on centers.

With this object in view, Athe present invention consists in the methodandimachine for grinding or polishing as hereinafter described andparticularly defined inthe claims. Y

In the accompanying drawngs, Fig. 1 is. a side elevation. partly insection of aimachine embodying the several features of the presentinvention; Fig. 2 is a front elevation showing so much of the machine asis necessary to an understanding ottlie present invention; Fig. 3 is aplan view of the machine shown in Figs. 1 and 2: Figl is a rearelevation of the work rest :'Fig. 5 is a. detail view in section on line5 5 of Figs3; FigQG is a. detail in sect`on online 6 6 of Fig. 1-; Fig7is a diagram in plan illustrating the operation of grinding orpolishingwith the machineot the present invention; Fig. 8 is a diagramsmilar to Fig. 7 but taken in front elevation; Fig. 9 isI a diagram inplan'illustrating the operationof taper grinding Without transverse feedFig. 10 is a front view of the belt tensioning mechanism: and Fig. 11isa side view of the belt tensioning mechamsm.

-. The preferred embodiment of the present invention comprises animprovement ontlie machine disclosed in the Blevney patentQNo.15594.445, dated `August 3; 1926,' in which the grinding or polishing ofstraight Work is effected by means of an abrasive element prefbeing fedover a suitable Work resttransversely of the abrasive elementl by asutable work holding andfeedmg dev1ce.j- This device, which may consistof a rotating roll,

causing the transverse movement of thewvork', .for which latter 4purposethe roll is inclined with respect to the center line of the Work.

about an axis substantially perpendicular to the plane of the abrasiveelement.

The principal feature of the present invention consists in means wherebythe work holding means is mounted to permit an automatic recessionthereof romthe belt in order to accommodate work of changing diameter assuccessive portions pass into engagement with the abrasive element. Thisfeature perm'ts the grinding of tapers, the work holding f meansautomatically.increasing its distance from above as the work passesthrough the machine. l e' In addition to the adjustmentl of the Workholding means about an axis perpendicular to thc abrading surface yforthe purpose ot feeding the Work, a further feature'of the presentinvention contemplates an adjustment thereof about an axis which issubstantiallyf parallel to the abrading surface in' order that itsengagement with the-work may conform to the work -surfa e, particularlywhentapers are to be gom or polished.-

Referring to the drawings, the illustrated embodimentl of thepresentinvention com prises the abrasive belt 10 and the bacling or cushionbelt12 which are 'caused totravel in the direction of the arrow of Fig. 1.vThe :backing belt 12 passes over the platen bars 14 which aresupportedon a carrier 16, and mounted :Eor suitable movementptoward .and from thebelt as described in above mentioned Blevney patent. The' work 18 issupported on a work rest indicated generally by 20 during 'the'polishing ,or grinding operation, and is maintained 'in engagementwiththe belt by meansof the rotating feed` roll 22,- constituting theywork holding `and yfeeding means. The feedroll is covered with leatherorj rubber and'is rotated inthe direction of lthefarrow in'order torotate the work and presentfall portionsthereof to the belt. The

feed roll22 isn-mounted ina. feed roll house which are driven lfromapulle-y28 connected by a belt 30 ywith a source of power, the belt fbeing maintainedtautby a tension or takeing 22f and is rotated by meansofgears 26. serves the double function ot .peripherally` supportingthework to maintainitin engagement `with the abrasivev -element and 10Qup means hereinafter to be described in detail. .The feed roll housingis provided with j bearings 32 to receive trunnions 34 extending fromopposite sides of a vertical supporting plate 36. The' feed roll housingmay be adjusted to .different angular positions by rotation -about thea'xis of the trunnions 34 which axis, it will be seen, isperpendiculOp-lar to the abrading surface of the belt 10.

The housing is maintained in adjusted posi tion by bolts 38.Thisinclination of the feed roll is for the purpose of imparting alongitudinal motion tothe Work as it passes over the work rest. Thedetails of the abrasive element and the feed rollthus far described varesimilar to ,those described in the above mentioned Blevne",7 patent.

In order to permit grinding of tapers, pro- A vision is made foradjusting the feed roll about. an axis parallel to the abrasive surface,

that is to say, a vertical axis in the illustrated machine. Provision isalso made for permitting a recession of the feed roll from itsinitialposition during the grinding operation `in order that the taperwork with its changing diameter may pass over the work rest Abetween thefeed roll and the belt.

To these ends, the plate 36, which constitutes a support for the feedroll assembly,

is formed with a base 40v to the bottom of which is secured a. post 42received in a suitable bearin in a' carriage 44. The base 40 rests upont e to of the carriage 44, and is secured in any drdsired angularposition lby means ofva..bolt46 threaded'into the carriage 44 andpassing through an arcuate slot 48 in the base l40. In order to .pxeventaccidental removal of the feed roll assembly from the machine, the post42 is formed'with an annular groove 50 into which extends the end of ascrew 52 threaded into the'front of thev carriage 44. It will be seenthat the center line of the post 42 is the axis about carriage assemblvguide piece being formed integral with .the

slide bearing 54, and the latter being adjustably-attached tol thebearing by means of bolts 68 received in the bearing and passing throughtransverse slots in the guide 66. The

guides engage withthe' carriage on inclined surfaces to'maintain thecarriagein p roper vertical position. p, One 'of the guldes is cut awayto provide a locking piece 70, which may be forced a ainst the side ofthe carriage by means of a hand screw 72 to retain thecarriage inany\desired adjusted posi tion, as inl the grinding or polishing ofstraight work where no movement ot' the carriage is necessasry. Acurtain 73 secured to the carriage and passing over a roller 74journaled in the forward end ofthe slide bearing protects againstentrance of dust into the moving parts. The free end of the curtain isprovided with a weight 7 5 to hold it taut.

The supports for the various parts are described as follows: The slidebearing 54 is bolted toa table 76 extending transversely across themachine and the table is secured to a plate 77 which is formedintegrally on the end of a vertical post 78. The post extends through ahole in a block 80 and the table with itsassociated mechanism issupported on the block by a collar 82, which is locked i to the post 78by a set screw 84. The block 8O is firlnly'supported upon the maincolumn 86 of themachine by two posts 88 which are secured to the column,and on which the block l 80 is slidingly mounted. In order that theentire assembly may be adjusted toward and from the belt, a rotatablescrew 90 is received in the block 80 and has its end journaled in abracket 92 secured to the column 86 between the two posts 88. A hand`Wheel 93 is used to impart rotation to the sc'rewin order to adjust theposition of the table and its associated 'mechanism with relation to thebelt. A curtain 94 similar to the curtain 73 is attached to the rear endof thecarriage to rotect the guides.

n order to maintain the feed .rollin proper position with respect to thework and to the belt as the grinding proceeds, a cord 95 is secured tothe rear end of the carriage 44 by means of a bolt 96Awhich is receivedin a slot in 'the carriage. From the rear end of the carriage the corddraws forwardly and passes over a pulley 98 downwardly to a secondpulley 100 andthence to the left side over a pul-v.

ley 102 journaled in the extreme left-hand `end of the table. A weight104 is attached to the end of the cord and acts to draw the carrlage andits associated feed roll assembly toward the belt. The. weight, beingplaced in .the position shown, also serves to counterbalance the feedroll assembly and to revent unbalancing of the table which might impartexcessive. stresses to the supporting posts. A stop 106 which projectsupwardly, through a slot108 in the bottom ofthe guide limits the forwardmovement of the carriage by engaging with the rear end of the latter'.The stop is provided .with a horizontal plate 109 which bears againstthe un-dersurfacc of the guide and which is secured in. any desiredposition by means, of a bo1t"112 assing upwardly through the s1ot108 anenmoana of the table is a plate 116 which is formed integrally with abushing 118. 'Ifhejwork rest -supporting post 120 is received in thebuslimg and has circular rack teeth 122 formed on its lower end. Thecircular rack engages with a pinion 124 which may be'rotated by a handwheel 126 to Araise or lower the post 120. Moreover, the post mayb'e-rotatedy about its axis to present the work rest in various angularpositions with respect to the belt. The bushing is slotted transverselyat 128 and also longitudinally in order to provide means for clam ingthe post 120 through the medium of a ock screw 130 as will be obv'ons.The post extends outwardly from the tab e) at such an angle that rackingof the post will produce a horizontal movement of the work rest which isabout one-half of the vertical movement.

, A mounting plate 132 is secured at the upper end of the post 120 and awork rest support 133 is pivoted on the 'mounting plate by means of astud 134, provision being made for locking itin. any adjusted positionby means of a bolt 136 secured in the mounting plate and passing throughan arcuate slot 138 in the support. The bolt 136 is positioned beyondtheouter edge of the abrasive belt,

j where' it is .conveniently 'accessible' for adjustment. The work restproper consists of a plurality of freely rotatable rolls mounted ona'pintle 142vwhich is journaledin a frame 144 secured by screws 146 tothe support 133. The rolls are maintained inspaced relation `byintermediate projections 147 formed integral with the frame 14,4.

.The work rest is therefore capable of four adjustments,'-iirst, acombined vertical and horizontal movement accomplished by racking thesupporting post up or down; second,

a horizontal movement effected by'bodily ad justment of the machine bedby actuation of the hand wheel 93 ;,third. an inclination on the pivot134 which is on an axis perpendicular to theabrading surface; andfourth, an angular adjustment between the plane of the work rest and theabrading' surface accom'- plished by rotating the supporting post 120 1nits bushing.

The first of these adjustments is of-es cial value in grinding Ystraightwork, cause if the diameter of the work is changed, the work rest may bemoved in one operation to a position which is horizontally the correctdistance from the belt and vertically correct to position/the centerline ofthe work at the proper level. If it is desired to` makeindependent vertical and horizontal adjust- -ments, the rest is firstmoved to its proper 'vertical position byrth'e supporting post, and itshorizontal position-Mis determined by the work rest andJ thel belt.

portance in fine polishing, as willI hereinadjustments, it will be notedthat a rotation of the post 120 will produce a corresponding tipping ofthe work Test due to the inclination-of the post from the-vertical, butthis tipping is ordinarily of no conse uence, and if necessary, may becompensate by an adjustment on the pivot 134.

In the operation of the machine the platen bars 14 are brought upagainst the belt and ,are secured in position as described in the indingstraight work, the operation is identlcalwith that described Blevneypatent. For

in theBlevney patent. The'work rest is adjusted so that the center lineof the work is slightly lower than the center of the feed roll. y

The feed roll carriage ismaintained stationaryby means of the screw 72.The work rest is positioned somewhat closer to the belt than to the feedroll inorderlthat thework -The adj ustmentabout the pivot 134 is of im-.l

after be described. As for the fourth of these v 'lol may not be jammedor cramped between the In order to cause feeding of the work through themachine', the feed roll is tilted on the trunnions 34, the axis ofrotation of the roll, however, being maintained parallel to the abradingsurface.

It is to be noted thatfor adjustment to di/fferent sizes of straightwork it is preferable to move the table as a unit by means of the handwheel 93 rather tha-n to lmove the carriage by loosening the screw 72.This operation moves both the feed roll and the work rest as a' unittoward or from the belt, but if the changes are such as toy necessitateindependent adjustments of the feed roll and the work rest, they may beeffectedv by moving the feed roll carriage in theslide bearing and byrackng the Work roll supporting post up or down.

For grinding taper work, the'machine is adapted for use in twoways,-irst, with transverse feeding of the work; and second, withoutfeeding. .In the first case, the parts are arranged as diagrammaticallyshown in Figs. 7 and 8. The work rest may be adjusted to any suitableposition aboutthe pivot 134,

loo

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being arranged for the operation illustrated in Fie' 8 so that the axisof the work is horilel to the' belt as'indicated by the dotted line2O()y in Fig; 7, and is ositioned between the belt and the center o thesmallest diameter of the work to be vground, in order that the worlinaynot be cramped or jammed by fa'll- Vertically the work rest is arrangedso that vertical axes which arerespectively desi- I )n'ated at,202 and204 of Figs. 7 and' 8. A 65 second of the above mentioned adjustments.justment about the verticalaxis 204, which 130 ving between the workrest and the feed roll.

zonta. The plane of the work rest is'paralis the asis of the bearig:isos-,45s

post.42, is made so vent passage thereof through the machine that theangle of the fee roll with respect or wherethe work is of extreme taper..In' to the belt may be made to conform to the this case, ithe parts areplaced as shown in surface of the taper as shown in Fig. 7. The Fig. 9.The work rest is preferably arranged amount of inclination on, thehorizontal axis at an angle with respect ,to the beltasshown .70 202 issuicient so that the axis of rotation by the line 20G-which is parallelto the center of the feeding roll and center lilieof the line of theworkrbut somewhatneare'rfY the ment of the. work and the fee work areoblique tos eachother, .the rate of beltthan the feed nroll. The feedrollis ad. feeding being determined by the inclinationl )usted about itsvertical axis 204` so that it between these lines. Although theengage-`contacts substantially .throughout its'entire lroll is a int length.with an elemental line of the taper.

' of contact because of the inclination o the This mayrequire that theaxis of rotationroll with respect to the axis of the work, the bemaintained substantially-horizontal, that adjustment of the roll aboutits taper axis i`s,without tilting 'on the-axis 20,2 but', espe- 204insures a uniform pressure of t e work cially in thecase of large taperit maybe against the belt during the entire grinding adjusted to lieparallel to thecenter line of operation. The carriage is unlocked by thework, and atan angle from the horizonloosening the screwj 72 and the sto106 is tal. The feed roll carriage, is preferably adjusted to such aposition that at t e comlocked in position` by th IOCkig Piece-70-mencement of the grinding operation the feed `(Inthis(operation, notransverse 'feeding' 516-' roll will be at a distance from the beltexactly v*tion takes place, the feed roll merely rotati suicient forreceiving the small eid of the ing the work` against fthe"I abrasiveele'` work. The work is preferably started with inent. Because of thefixed position'of the a'considerable portion of its len 'against thework, however, by the action of\o rationsvand to cross the feed.roll-areshowi infulllinesinFig'. 7 for intoan angular position aboutthe axis ,ofthe x the ycommencement of the grinding operation 'stud 134.This gives a high lusterand climi-r gth in engage- =fed roll/carriage,this operation permitsA ment with the abrasive belt. f i grinding oftapers with considerable accu- As lthe grinding progresses, the feedroll racy ,although the length of the work ywhich performs the twg-foldfunction of holding can be successfully ground is limited by the theworkagainst the belt and'adva'ncing it width of the belt. from left toright. As `the work advances, While the work rest is preferably maintmoves with ,its axis always parallelto it- @tained horizontal for normalwork, the piv-- self, and because of the increasing diameterotaladjustment. on the stud 134 is' a'feature of' the work, the feedingaction causes the of importance lforpermitting'fine .polishing f feedroll carriage to be moved Vforwardlyor on soft metalssuch as brass. Inthis case, it is away from' the belt, being 'pressed' firmly desirableto perform a pluralitylofhpolislhing is ingin s. the weight 104. Thework'is therefore moved. o this end, the`work isiirst through hetransversey of the feednroll, and the feed' machine with'thework restina substantially roll Ais m ved f longitudinally by the work; horizontalLposition and is passed through The relative positions of the' work andthe a second time after'therest'hasbeen adjusted andin dot and dash.ylines for the conditioAn L nates any polishing marks on the work. f

when fthe work has progressed part way. It will'be apparent from thef.diameterbf the latter, and as'th grindingv automatically dischargedfrom the rightl ofthe weight.

1 Emplo 'work wit out feeding is useful in ca'ses where its outer end a'counter balance`- w 6.5-

work, inforder that 'the roll may not have out of engagement with thework rest. At

for another grind Oregomg de: through the machine. At the commencementl'lscription that 'during polishin vand grindf of the operation, thepoint of contact of the` ing of taper work. a considerab @latitude of110 feed roll and the wo k occ 'rs at thex smalll vmovement is required'for the belt 3 0 becausev `of the movement of the feed roll cariia e-andthe necessary tip ing of the feed( rol .Y To( 'the @dft-har the galegomay/be maintained taut under all conditions, "the vtakeup'means` 115illustrated in Figs. 10= and 11 is emploed.'`-` The belt 30 passing overthe feed roll pu ley`-r 28is driven by a'pulley 160 fast on a shaft162., which is journaled in'a bracket 1641secured ai bya post 166 to .lthe main columnJ of the in a- 120 cliine. A driving pulley168connected'with s roceeds this oint of contact occurs on lower evelswith peet to the workI axis and on higher levels with .respectjto'thefeed roll ams.'w It is desirable that the point of contact be maintainedat alevel not higher thanthe axis of the feed roll for all positions ofthe `any tendencyf to :force the work upwardly the completion of theoperation, the work is P rotate the. shaft 162.' Anf idlerarm '170 handside of the machine and-thelcarriagis formed integral fw'ith ,a hub .172which is restored to lits-'original position iii readiness looselyreceived on the shaft :162, carrieatwo 125 ingj operation by'tlie actionspaced idler'pulleys 17 4( overlwhich the belt 30 passes;4A'counterbalance armll-galso formed-integrakwith the hub 172,'carries atei ht 178 the work hasprojections `which would pre-' which acts tomaintain-the ridler pulleys in 130 ent of the mithin@ to grindip'r,

any suitable drivingmeans is 'employed to i engagement with l'the beltin a manner to maintain the belt taut under all conditions.

The wei ht is pivoted on the arm 176 by means o a stud 180. The positionof the part when the yfeed' roll is in itsrearwardmostl position, viz,its position ne rest the abrasive ,'belt, is indicated in full ines inFig. 11. Drin the operation of grinding taper work,l the feed rollcarriagemoves forwardly so that the feed roll pulley 28 may finally takethe position indicated'in dot and dash lines. The positions of the belt30 and the counter balance arm are also i lustrated for this position bydot andfd'ash ines. It

-will be seen that by the employment'of two spaced idler pulleys whichare capable of simultaneous movement on the idler arm, the belt may bemaintained taut by a movement of the lidler arm which is 'only half ofthat which would be necessary' if only a single to a lmore nearlyvertical position, where the counter balance 178 exerts a decreasedtensioning force. In order to permit the counter balance to approachmore closely this vertical position upon raising of the counter balancearm, the weight .is'grooved at 182 to provide a recess into which thearm may enter.

The above arrangement of the belt take-up mechanism provides for-suicient pressure of the idler pulleys against the belt for proper,

tensioning ofthe belt under all conditions any axis. The id er pulleys174: are arranged sufficiently above the feed roll pulley 28, and thebelt 30 is of suicientl length so that the belt may pro rly enga e thegrooveof the feed roll pu ley even t ough the latter isA tipped to aconsiderable angle. In order to eliminate any 'possibility ofdisengagement of the belt and pulleys however, the latter are formedwith deep the belt is of comparatively small cross section, fittingsnugly within the grooves of the pulleys;

It will be seen that an important feature inl connection .withgrinding-of tapers consists in the provision for `mounting the feed rollfor adjustment `about two axes, one of which is substantiallyperpendicular lto the abrasive element, and the othe` of which is Y Y Ysubstantially parallel thereto. Stated in an- .other way, the tippingaxes of the feed roll -shaped grooves and diameter. independently of themovement of the car-l riage or of the tipping of the'feed roll abouttiall perpendicular to the axis yof rotationof the eed roll. f

It is to be understood that the inventionl is not considered tobelimited to the specificconstructionherein shown and' described but maybe varied insofar as iti does not depart from the scope of theappenledxclaim's. 'It is within the purview of the invention, forexample, to employ7 an abrasive element in the form of a grinding rollin place of a travaremutually perpendicular and yare substani ellingbelt, in which case the positions ofthe v axes which are defined asbeing respectively per endicular and parallel to the abrasive sur ace,will be considered to be substantially perpendicular and parallel to a"tangent plane of the abrasive surface atjthe position of Contact of theabrasive element with the work. f

Having thus describedthe invention, what is claimed is:

1. A grinding or polishing machine havi ing, in combination, a vrorkrest, an abrasive element, a work holdingy and feedingdevice to engageperipherally with thework and to feed it transversely of the abrasiveelement,

and meansfor mounting. the@ abrasive element andthe work holding'y andfeeding device having provision for recessive movement between them, andmeans for causing relative movement between the vwork holding andfeeding device and the abrasive element as' 'the grinding or polishingproceedsito accommodate taper work.

2. A grinding or polishing machine hav# ing, in combination, a work restan abrasive element, a work holding device for peripher Aally supportingthe work, and means for rotatably adjusting the work holding deviceabout an axis substantially parallel to the direction of movement of theabrading sur- M face to accommodate work of non-uniform 3. A grinding'or polishing machine having, in combination, an abrasive element, awork rest, feed roll for peripherally supporting the work in engagementwith the abrasive element and for feeding the work trans versely of theabrasive element, and means for causin recessive movement of the feed ofthe work to accommodate work of nonuniform diameter.

roll from t e abrasive element during feeding 4. A grinding orpolishing`machine-having, in combination, an abrasive element, a Work rest, a feedroll for feeding the work transversely of the abrasive element and formaintaining it in engagement therewith,

means for adjusting-the inclination of the'- feed roll about'an axissubstantially perpen- -dicular to the abrasive element, and means formounting the feed roll having provision 'for progresslvely varying thedlsta-ncebetweenthe feed roll and the abrasive element to accommodate'work iof changing diameter. 1.30.`

5,. A grinding or polishing machine havlng, in combination, anvabrasive'element, a

work rest,v a feed roll for feeding the work,

transversely .of the abrasive felement and for maintaining it inengagement therewith, means for adjusting the inclination of the feedroll about an axis substantially erpendicular to thev abrasiveelement,an means for causing the feed rollte recede from theabrasiveelement as the grinding progresses to accommodate work ofincreasing/diameter.

6. -A grinding or polishing machine having, -in combination, an abrasiveelement, a

work rest, a feed roll for feeding the work transversely of the abrasiveelement and for y maintaining it in engagement therewith,

i means for adjusting the-,inclination of the feed roll aboutan axissubstantially perpendicular'to the abrasive element, means for rotatingthe feed roll, means for slidingly mounting the feed roll, means forprogressively movingthe feed roll from or toward the abrasive elementlas the grinding rogresses, and means for maintaining the eed roll inengagement with the work irrespective of the variations 'in diameter ofthe work.

7. A- grinding or polishing machine having, in combination, an abrasiveelement, a

, work rest, a feed roll, means for rotating the lto slide back andforth with relation to-the abrasive element,,a support for the slidebearing arranged atv one side of the bearmg, a

' weight and connections-therewith for, maintaining the feed roll inengagement with thel work, the weight being positioned at the oppositeside of the`support on the slide bearing to counter-balance the latter.9. lA grinding or polishing machinehaying, in combination, an. abrasiveelement, a feed rolladaptedl to en age the work on the oposite side fromt e abrasive element and aving' rovision for tipping.. about mutuallyperpendicular axes which are substantially perpendiular to the axis ofrotation, awork rest, a supportfor the feed` roll lnavmgz;` rovision forpermitting bodily recession o the feed roll from the abrasiveelement-'for grindin orlpoli'shing tapers, and means Iforv maintamingthe feed'l roll in engagement with the work during thegrindingorpolishingfoperaftion; f

.ing, in combination, an abrasive e1'ement, a an angular adjust/mentLof, the plane of the v10.` A grinding or polishing machine l havfeedroll to feed the work transversely of the abrasive element, a work rest,a slide bearin for the feed roll, means fr causing the feed roll tolrecede progressively from the abrasive element during feeding of thework toY accommodate taper work.

ing, in combination, an abrasive element,a work rest, a feed roll tofeed` the work trans,- Jverselyof .the abrasive element, a vfeed rollhousing pivoted on an axis substantially perlL- Agrinding or polishingmachine havpendicular to theabrading surface', a'carriage f on which.the housing is mounted, a slide bearf ing in which the carriage hasprovision for longitudinal.v movement toward and away from the abrasiveelement, and means for causing progressive movement of the carria on theslide2 bearing asthe feeding of e work proceeds to or polishing of taperarticles.

12. v A' grinding ori-polishing machine hav- `ing, ingcombination, anabrasive element, a work rest, a feed roll to feed the work transeversely of the abrasive element, a feed roll carriage, means formounting the feed roll on the carriage having provision for tip ing ofthe roll on axes substantially perpen icular and parallel to theabrading slwxrface respectively, anda slide bearing in which the' l'carriage is free to move toward or away from the abrasive elementduring transverse 'feed of the 'work to permit grinding o1" polishing oftapers. .V5 v 13. A grinding or polishing machine'having, incombination, an abrasive element, a.

Work rest, a feed rollto feed the work transversely of the abrasiveelement, means perfnittng tipping of the feed rollun mutually.perpendicularaxes which are substantially eifldiczular to the ofrotation .of the roll, a sliding 'carriage on which the feed rolLismounted and adapted o move away from the abrasive element during feedingand grinding of taper work, and means forvlocking the carriage for ofstraight` work or of ta er work without feeding. 14. 'A grin ing orpolishing, machine having, in.' combination, abrasive lelement, a

` work restpmcans'for maintaining the workin engagement with .theabrasiveelement, and ,means for adjustingthe work rest todiierent1angular positions to vary the angle bef ,the work rest andAthe' i machine havatable for supporting the feed rolhav work rest,- workrest supporting meansv f 'extending outwardly from the table and con- Istructedand arrai'aged` Lto eie'ct a simultaneous verticaland-horizontal adjustment offthe' work rest, and means for mountingthewrk i rrest supporting mean'shaving provision for belt.

work rest with respect to the abrasive element.

16. A grinding-or polishing machine having, in combination, an abrasiveelement, a

-feed roll, a table for supporting the feed roll,

a work'rest, a work rest supportingpost extending on an angle from thetable and toward the abrasive element, a .bushing secured to the table,a rack'formed on the supy porting post, a pinion engaging with the rack`mitting turning adj ustmentsJof the work rest, and means for clampingthe su ported post.

18. A work rest for a center ess grinding or polishing machine,comprising a series of. rollers with which the workengages a pintlehaving its axis below and substantially parallel with the work on whichthe rollers are mounted for free rotation, anda support for the pintle.l

19. A work rest for a centerless grinding or polishing machine,comprising a su porting plate having a plurality of upwarly extendinprojections, a intle extending throng the plrojections, an a series offreely rotatable ro ers mounted on the pintle be'- cient pressuretomaintain the belt positions of the feed roll.l I

'22. A grinding or polishing machine having, in combination, an abrasiveelement, a work holding and feeding device, a carriage taut at an topermit movement of the work holding and feeding device with respect tothe abrasive element, a belt for driving the work holding and feedingdevice, means for maintaining the belt taut at all positions of thecarriage including an idler pulley anda counter balance, and means formounting the counter balance having provision for permitting a decreasein the tensioning effect on .the belt as the carriage recedes from theabrasive element.

In testimony whereof I have signed my name to this specification.

RUFUSFULLER.

tween the projections :for supporting the l work.

20. A grinding or polishing havin, in combination, an abrasive element,a wor holding and feedin device,` a ulley 'for thework holdingmn feedingi)evice, means permitting lon itudinal and inclined movements of theyvorV holdin and feeding device, a belt associated with le pulley foroperating the device, means for maintaining the belt taut includingspaced idlerpulleys adapted forv simultaneous movement, and

machine .j

means for maintaining the idler ulleysin engagementwith oppositesides o4the belt and under suicientpressure to tension the 21. A grinding orpolishing machine having, in combination,'an abrasive element, a l feedroll, a feed roll carriage to permit movement of the feed/roll .withrespect to thev abrasive element, iieansv permitting inclination of thefeed roll, a belt for driving the feed roll, an idler arm, a pairof'spaced idler pnl-- -leys mounted on the vidler arm and adapted' forsimultaneous movement, and a counter-9 balance associated with the idlerarm for?,

maintaining the idler pulleys in engagement with opposite sides 4of thebeltv under sum-

